N/A
Hyperboloid electrical contacts or contact sockets are known for their reliability, resistance to vibration, low insertion force, low electrical resistance and high number of insertion/extraction cycles. A conventional hyperboloid contact socket includes an inner tubular sleeve which is open at both ends and which is located coaxially within two cylindrical sections that form an outer shell. The distal end of one of the outer sections is machined to form a cavity for permanently affixing wires to the contact either by soldering or crimping. Alternatively the distal end can be machined to form a pin to be soldered or press fit into a circuit board, or used to affix wires by wrapping them onto the pin. The proximal end of the second outer cylindrical section remains open to receive the male pin of a mating connector or device. A plurality of loose, or floating wires is arrayed within the inner sleeve to form the shape of a single sheet hyperboloid. At each end of the inner sleeve the wires are bent 180xc2x0 outward so as to return axially between the inner and outer sleeves. The wire ends are thereby retained at each end of the inner sleeve by means of a press fit between the wires and the inner and outer sleeves as shown in the prior art FIG. 1. Some form of rolling, crimping, swaging or other suitable means to provide mechanical and conductive attachment is used to affix the outer sleeves at or near the axial midpoint of the inner sleeve. This contact configuration has been in use for many years and is known to present a difficult assembly task and to require expensive, high precision machined components. Additionally, due to the nature of the press fit retention of the wires, it is not uncommon for the wires to become separated from within the inner and outer sleeves, particularly during usage of the contact, thereby leading to field failures of the device in which it is in use. Additionally, this type of field failure can lead to damage of the mating male connector elements, further exacerbating the extent and cost of repair of the overall system in which the contact has been deployed. In addition, because of the concentric arrangement of the inner and outer cylindrical sections and the retained contact wires, the contact structure is larger in diameter than other forms of contacts and cannot therefore be used in applications requiring higher contact density, or in applications requiring the characteristics set forth above where miniaturization must be realized. Examples of prior art constructions are shown in U.S. Pat. Nos. 3,107,966, 3,229,356, 3,470,527 and 6,102,746.
It would be useful to provide a hyperboloid contact socket having a smaller outside diameter to permit use in applications requiring closer center distance spacing. It would also be useful to reduce the cost of manufacturing through the elimination of unnecessary parts and through improvement in the efficiency of assembly by permanent and conductive attachment of the contact wires into position within a contact body to form the hyperboloid contact area. It would also be useful to provide a contact socket which can be separately fabricated apart from a specific termination type, which subsequently can be readily affixed to different termination types. It would also be useful to provide a contact socket where the need for costly machined components is reduced or eliminated.
In accordance with the present invention, a hyperboloid contact socket is provided which can be manufactured in a cost efficient manner using automated high speed manufacturing processes and wherein different types of terminations can be affixed to the contact socket as desirable for user requirements. The contact socket comprises a tubular body of metal or other suitable conductive material and preferably having at one end a lip defining an entrance aperture for receiving a mating pin terminal and having on the opposite end a termination of an intended configuration for attachment to a circuit board or other device or item. The tubular body contains a plurality of conductive wires welded or otherwise conductively and permanently affixed at their respective ends to respective inner surfaces at or near the outer and inner ends of the body and disposed in an angular disposition to form the shape of a single sheet hyperboloid. The body is preferably manufactured by deep drawing which is less expensive than precision machined parts usually required by conventional designs. The wires are preferably laser welded within the tubular body and are permanently attached directly to the inside of the tubular body. No additional sleeves or tubes are necessary to secure the contact wires as in conventional hyperboloid contacts. The novel contact socket can therefore have a diameter substantially less than that of conventional hyperboloid contacts for a given current rating, and the reduced diameter permits the novel contact sockets to be more densely packed for use in a connector, circuit board, device or other installation.
The process of fabricating the contact sockets can be implemented by high speed automatic equipment and assures consistent attachment of the contact wires within the tubular body. It is a benefit of the novel contact socket that the body containing the welded or otherwise conductively and permanently affixed wires, a subassembly denoted as the wire contact assembly, can be fabricated separately from the termination end. As a consequence, the same wire contact assembly can subsequently be attached to various termination types to suit utilization requirements. Typical termination types can be crimp, solder cup, pin or surface mount. As allowed by its configuration, the termination end is preferably manufactured by deep drawing which, again is less expensive than precision machined parts usually required by conventional designs.
In one aspect of the invention a mandrel employed to orient the wires within the tubular body during fabrication of the contact socket remains attached to the tubular body after assembly of the contact wires and serves as a connecting pin to which various terminations can be attached. This aspect of the invention provides conductive and permanent attachment of the wires to the tubular body and to the mandrel through deformation of the body, preferably by rolling, crimping, swaging or other suitable means.